Preparation of certain hydroxamic acids



United St tes Piero M. Carrara, Milan, Italy N Drawing. Application July 9, 1957 Serial No. 670,641

Claims priority, application Italy July 13, 1956 2 Claims. or. 260-500) Cycloserine is an antibiotic streptomyces.

Its chemical structure is that of D-4-amino-3-isooxazolidone.

Its synthesis has been described. by American authors in J.A.C.S., 77, 2347 (1955), starting from DL-serine, by conversion of this aminoacid into its methyl ester, condensation of the same with ethyl imino benzoate into the corresponding oxazoline, conversion of the latter into the corresponding hydroxamic acid, chlorination of this last-named compound with opening of the oxazolinic ring' and re-condensation of the chlorohydroxamic acid into substituted isooxazolidone.

The latter is then opened again with hydrochloric acid and the methyl ester of a B-amino-oxyalanine is obtained, from which racemic cycloserine is finally obtained with loss of the benzoic radical.

Racemic cycloserine thus obtained may be separated into its active components by means of tartaric acid.

We have found that it is possible to prepare cycloserine and its derivatives starting from beta ketonic acids and their derivatives.

R COCH COOK (I) These products are then transformed into the corresponding alpha acyl amidic acids R1COCIJH-COOK IIIH COR: (II) transformed in the alpha methyl produced by a strain of These are subsequently condensation products.

l a err-0H 111-0 0-(5-00011 1TH CORg (see Carrara G., DAmato V., Ital., 1950, 822).

From the Compound III, it is possible to go on, following the procedures described below with protection of the CO by transforming it into the corresponding hydrazone by means of an hydrazine:

(1) 0xamation.Substitution of (III) Bellenghi M., Gazz. Chim.

(3) Condensation.-Condensation of (V) into 4-acylamino-3-isooxazo1idone-4-acyl-5-R (VI).

(4) Ring opening-Opening of the oxazolidone (VI) to obtain the beta amino-oxy-alpha-acyl-ester of a beta substituted alanine (VII).

2,929,836 Patented Mar. 22, 1050 (5) Cl0sure.Cl0sUre to racemic 4-amino-5-R substituted 3-isooxazolidone (racemic S-substituted cyclo serine) (VIII).

(6) Amipods separati0n.'Separation of the antipods 0f (VIII) (IX).

A step l-bis consisting in the closure of an oxazolinic ring between the fi-oxydryl and the carbonyl of the acyl to the a-amino group of the serinic chain of the Compound III may go before all the above mentioned steps.

R in (III) may be an alkyl or aryl (substituted or not), an aralkyl or a heterocyclic ring (substituted or not), or an alkoxy radical; R may be an alkyl or aryl, aralkyl or ethero cyclic ring (substituted or not); R may be an alkyl, aryl, aralkyl, or a heterocyclic ring (furyl or thienyl) (substituted or not); R is an alkyl with a C to C chain.

In the case that R is an alkoxy group, a supplementary step 5 his will be necessary, in which a semisaponification or decarboxylation takes place, before or after step 5.

Steps 1 to 6 may be changed in their subsequence, e.g.:

The above mentioned changes are possible also with an optically active Compound III, in which case an optically active isooxazolidone (cycloserine) is obtained.

EXAMPLES Example 1 0.04 mol. of alpha-acetylamino-alpha-benzoyl-beta-hydroxy methyl propionate (III) is treated at cool temperature with concentrated sulfuric acid. The solution is then sprayed on cracked ice, the mixture is neutralized with an alkali metal or alkaline earth carbonate, filtered if necessary, and extracted in ether. 2-methyl-4-benzoyl-4- carbornethoxy-4-oxazoline is obtained from the extract.

Example 2 Example 3 0.05 mol. of alpha-benzoylamino-alpha-acetyl-beta-hydroxy ethyl butyrate (III) is treated in acetic acid with phenyl-hydrazine. The phenylhydrazone of alpha-benzoylamino-alpha-acetyl-beta-hydroxy ethyl butyrate pre-' cipitates.

Example 4 The alcoholic solution of an equivalent of hydroxylamine is added to an alcoholic solution of the phenylhydrazone of alpha-benzoylamino-alpha-acetyl-beta-hydroxy ethyl butyrate. The mixture is agitated at room temperature 24 hrs., and the phenylhydrazone of the alpha benzoylamino-alpha-acetyl-beta-hydroxy-butyrhydroxamic acid (IV phenylhydrazone) is obtained.

Example 5 The alcoholic solution of an equivalent of hydroxylamine is added to an alcoholic solution of alpha acetylamino alpha benzoyl-beta-hydroxy methyl propionate. The mixture is agitated for 24 hrs. at room temperature and the alpha-acetylamino-alpha-benzoyl-beta-hydroxypropionhydroxamic acid (IV) is obtained.

s r 2,929,886 1 f Example 6 An ether solution (at of alpha-acetylamino-alphaacetyl-beta-hydroxy propionhydroxamic acid is treated with thionyl chloride and agitated for 2 hrs. The ether is evaporated under vacuum, the residue is re-dissolved in cold pyridine and poured in ice made alkaline by means of Na carbonate. The 2-rnethyl-4-acetyl-4-hydroxamic acid of the 4-oxazolidine (IV bis) is obtained.

Example 7 The 2-methyl-4-acetyl-4-hydroxamic acid of the 4-oxazolidine (IV his) is boiled 1 hr. with conc. HCl. The beta chlor-alpha-acetyl-alpha-amindpropionhydroxamic acid (V hydroxamic) is obtained by extracting with ether.

Example 8 7 Example 9 Alpha benzoylbeta-chlor-alpha-amino methyl propionate (V) 'is treated in alcohol with the calculated amount of hydroxylamine. 24 hrs. later alpha-benzoyl-beta-chloralpha-amino propionhydroxamic acid (V hydroxamic) is obtained by distillating the solvent under vacuum.

Example 10 Alpha amino-alpha-acetyl-propionhydroxamic acid is treated at a temperatureof 10 to 30 C., with aqueous KOH (5% to corresponding to l to 3 moles and the mixture is agitated 24 hrs. The 4-acetyl-4-amino-3- isooxazolidone crystallizes by acidification at pH 6.

Example 11 Alpha-amino-alpha-benzoyl propionhydroxamic acid is treated at a temperature of 60 to 80 C., with aqueous KOH, corresponding to 1 to 3 moles and the mixture is agitated 24 hrs. The 4-amino-3-isooxazolidone crystallizes by acidification at pH 6 (racemic' cycloserine) M.P. 140-142" C.

Example 22 1 mol.fof 4-ben'zamino- 4-acetyl-3 -iso'o'xazolidone is treated in methyl alcohol with gaseous HCl. Beta-aminooxy-alpha acetyl methyl alaninate (ii-hydrochloride is obtained.

Example 13 Alpha-amino-oxy-alpha-benzoyl alanine ethyl ether, is treated at a temperature of to C. with 30% aqueous KOH, corresponding to 1 to 3 moles and the 4' a mixture is agitated 24 hrs. 4-amino-3-isooxazolidone crystallizes by acidifying at pH 6 (cycloserine) M.P. -142 C.

Example 14 Alpha-amino-alpha-benzoyl-S-chlorpropionic acid hydrochloride is separated into its optical antipods by means of its brucine salt. D-alpha-amino-alpha-benzoyl-betachlorpropionic acid and L-alpha-amino-alpha-benzoylbeta-chlorpropionic acid hydrochlorides are obtained.

Example 15 L-alpha-benzoyl-alpha-amino-beta-chlor methyl propionate, is treated in alcohol with the calculated amount of hydroxylamine. 24 hrs. later, L-alphabenzoyl-alphaamino-beta-chlorpropionhydroxamic acid is obtained by evaporating the solvent.

Example 16 droxylarnine in ethyl alcohol to produce beta oxy-alpha acetylamino-alpha benzoyl propionohydroxamic acid.

2. The process which comprises reacting beta-oxyalpha-acetylamino-alpha-benzoyl-propionhydroxamic acid of .the formula:

0 Nn-ii-ona H with an ionizable 'halide to produce beta-halo-alphaacetylamino-alpha-benzoyl-propionhydroxamic acid.

References Cited in the file of this patent UNITED STATES PATENTS Holly Nov. 27, 1956 OTHER REFERENCES Kuehl et al.: I. Am. Chem. Soc., vol. 77, pp. 2344-7 (1955).

Carrara et al.: Gazz. Chim. et al., vol. 80, pp. 822-830 (1950). 

1. A PROCESS WHICH COMPRISES REACTING BETA-OXY-ALPHAACETYLAMINO-ALPHA BENZOYL-METHYL PROPIONATE WITH HYDROXYLAMINE IN ETHYL ALCOHOL TO PRODUCE BETA OXY-ALPHA ACETYLAMINO-ALPHA BENZOYL PROPIONHOHYDROXAMIC ACID. 